If `alpha` is the degree of dissociation of `Na_(2)SO_(4)` the van't Hoff's factor (i) used for calculating the molecular mass is

Options

A. `1+alpha`
B. `1-alpha`
C. `1+2alpha`
D. `1-2alpha`

Answer

C

Explanation

`{:(,Na_(2)SO_(4)(aq)hArr,2Na^(+)(aq)+,SO_(4)^(2-)(aq)),("Initial conc",C,-,-),("At eqm conc",C(1-alpha),2Calpha,Calpha):}`
`i=(C(1-alpha)+2Ca+Calpha)/(C )=1+2alpha`